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next PZ lens test report: Pentax SMC FA 31mm f/1.8 AL Limited
#1
A re-test obviously. No surprises - a great lens:

[url="http://www.opticallimits.com/pentax/735-pentax31f18k5"]http://www.opticallimits.com/pentax/735-pentax31f18k5[/url]
#2
Why no bokeh assessment?
#3
[quote name='Brightcolours' timestamp='1337329181' post='18276']

Why no bokeh assessment?

[/quote]



An 31mm lens on APS-C (="48mm f/2.5") is not really an obvious candidate for this.
#4
[quote name='Klaus' timestamp='1337336079' post='18277']

An 31mm lens on APS-C (="48mm f/2.5") is not really an obvious candidate for this.

[/quote]

f1.8 makes it more of an obvious candidate though... Even at f2.7 (not f2.5) equivalent you still can get a lot of blur in images, and then bokeh assessment is not so strange.



What I notice from images taken with this lens is very nice bokeh with relatively up close scenes, like here:

http://www.robertsdonovan.com/?p=1148

but rather unattractive bokeh when the background is further away:

http://farm4.static.flickr.com/3550/3524...48a2_o.jpg

http://www.flickr.com/photos/[email protected]/536653623



Not double edged nissen bokeh horror, but a kind of "blooming" in the bokeh which I have also noticed with my Canon EF 35mm f2 (but to a lesser extent!).
#5
[quote name='Klaus' timestamp='1337336079' post='18277']

An 31mm lens on APS-C (="48mm f/2.5") is not really an obvious candidate for this.

[/quote]





[quote name='Brightcolours' timestamp='1337338209' post='18278']

f1.8 makes it more of an obvious candidate though... Even at f2.7 (not f2.5) equivalent you still can get a lot of blur in images, and then bokeh assessment is not so strange.

[/quote]



Great to see this re-test this lens.



But, I have to agree that if one is buying this lens then it's probably to use at the wider apertures and bokeh is of interest.



Looking at my images from one the Sigma 28mm f/.8 II lenses (a poor man's FA31 f/1.8!), it was a often candidate to seperate foreground/background, even stopped down to f/2.8:



@f/2:

[Image: p312431158-4.jpg][Image: p204449938-4.jpg]



@f/1.8:

[Image: p629371117-4.jpg]

[Image: p549617404-4.jpg]



Darn, why'd I sell that lens...I'm still poor.

<img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='Big Grin' />
#6
[quote name='Klaus' timestamp='1337336079' post='18277']

An 31mm lens on APS-C (="48mm f/2.5") is not really an obvious candidate for this.

[/quote]



Canon EF 35mm f/2 (APS-C)

[quote name='Klaus']

Bokeh (out-of-focus blur)

The EF 35mm f/2 is a fairly "fast" lens so it seems to be an attractive option for shallow depth-of-field situations - on paper.

http://www.opticallimits.com/canon-eos/1...0d?start=1

[/quote]



[quote name='Klaus']

Sony 30/2.8 DT Macro

http://www.opticallimits.com/sony-alpha-...dt?start=1



Sony 35/1.4G

http://www.opticallimits.com/sony-alpha-...14?start=1



Sony 35/1.8 DT

http://www.opticallimits.com/sony-alpha-...dt?start=1



Samsung NX 30/2

The NX 30mm f/2 behaves like a "46mm f/2.8" in terms of depth-of-field. This is just sufficient to isolate your main subject from the surroundings but you should keep a rather close focus distance to pronounce the effect.

http://www.opticallimits.com/samsungnx/6...f2?start=1

[/quote]



<img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/tongue.gif' class='bbc_emoticon' alt='Tongue' />
#7
And the funny thing is that the Canon EF 35mm f2 really is an attractive option for shallow depth of field situations... not just on paper.
#8
Sadly, while it is an attractive option; it does a very poor job (from the images I've seen).



[quote name='Brightcolours' timestamp='1337417633' post='18298']

And the funny thing is that the Canon EF 35mm f2 really is an attractive option for shallow depth of field situations... not just on paper.

[/quote]
#9
[quote name='you2' timestamp='1337418733' post='18300']

Sadly, while it is an attractive option; it does a very poor job (from the images I've seen).

[/quote]

That is not true at all, unless you base that on just that photo on Klaus' review.



Just a random selection of images taken with the 35mm f2 which show front and/or background bokeh:

http://www.flickr.com/photos/[email protected]/4684444058

http://www.flickr.com/photos/pooldodo/46.../lightbox/

http://www.flickr.com/photos/jcftang/467.../lightbox/

http://www.flickr.com/photos/virtualwolf.../lightbox/

http://www.flickr.com/photos/[email protected]/6200897077

http://www.flickr.com/photos/[email protected]N00/4628509371



Not bad at all for a 35mm lens. Yes, there are some that do better (Sony 30mm macro, some Zeiss 35mm lenses come to mind, as does a Leica Summarit 35mm f2). But really, for a 35mm lens the EF 35mm f2's bokeh is really quite respectable. And yes, with 5 sided highlights when stopped down.



I know this little lens well, I know its bokeh character quite well:

[Image: gallery_10230_17_71978.jpg]

[Image: gallery_10230_17_1903.jpg]

[Image: gallery_10230_25_338891.jpg]

[Image: 8DE91F04E0CC47B68BD04EC759436139.jpg]

[Image: 4285ADA295BB46E38D51E7954E412956.jpg]

[Image: 1ECF4413380D4203B4EE916CA9884648.jpg]

[Image: DE871742F86B4705872603D0753F1BD4.jpg]

[Image: gallery_10230_17_157078.jpg]





It does quite well. Saying that it does "very poor" could not be more beside the truth. In situations where it does not do a good job, other 35mm lenses will mess up too. Like in that infamous PZ review shot.

It does not have a busy nisen bokeh, like some other 35mm lenses show. It has smooth bokeh. It can show that "blooming" in the bokeh I mentioned in a post above. It does show 5 sided highlights when stopped down enough.



Even Mike Johnson, who introduced the word "bokeh" to our photography terminology to describe quality of blur, rated the Canon EF 35mm f2 as "7" on a scale from 1 to 10.

In comparison to some other rated 35mm lenses:

Olympus OM Zuiko 40mm f2 a 7.

Leica 35mm Summicron-M (4th generation) a 10.

Konica Hexanon 40mm f1.8 a 3.

Zeiss Contax Distagon 35mm f2.8 a 5.

Zeiss Contax Distagon 35mm f1.4 a 5.

Nikon AF-Nikkor 35mm f2 a 6.

Leica 35mm Summicron-R a 6.
#10
I don't know; we've drifted off topic. My comment was based on more than just Klaus review; but as you've shown the lens can be made to produce decent blur. Part of the issue is the optical design; but it could also use a few more blades; as well as a bit of flare resistance and .... Having said that it is relatively inexpensive and reasonably sharp so not bad for an old design. Anyways we should probably stick to commenting abuot the pentax lens in this thread (for which I have no comments).
  


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